Altered endothelin-dependent regulation of blood pressure and vascular tone in stress-sensitive august rats.

The endothelin (ET) system was studied in August rats, with genetically determined high sensitivity to stress, and in control Wistar rats. Radioimmunoassay revealed a significant difference in plasma endothelin-1 (ET-1) levels of August vs Wistar rats (7.1 fmol/ml vs 50.0 fmol/ml). Immobilization of the animals increased these values up to 11.0 fmol/ml and 65.2 fmol/ml, respectively. Elevation of ET-1 was associated with an increase in blood pressure, which was similar in both strains, whereas the heart rate increase was diminished in the stress-sensitive rats. The mixed endothelin-A/endothelin-B- (ET(A)/ET(B)) receptor antagonist PD142893 suppressed stress-induced elevation of blood pressure in August, but not in Wistar rats. In both strains, heart rate responses to stress were insensitive to the ET receptor blockade. Aortic rings of August rats displayed diminished sensitivity to the vasoconstrictor action of ET-1 vs that of Wistar rats (EC50 = 22.1 nM vs 6.3 nM, respectively). In noradrenaline-precontracted tail arteries, 50 nM ET-1 elicited further constriction without any vasodilator effects. ET-1-induced increase in perfusion pressure was greater in tail arteries of Wistar rats. Thus, endogenous ET-1 can play a strain-dependent role in the stress-induced responses of haemodynamics and the alterations in endothelin-dependent regulation may be responsible for the differences in vascular reactivity of Wistar and August rats.

[Activity of renin-angiotensin-aldosterone system (RAAS) and vasopressin level in patients with primary pulmonary hypertension]. / Aktivnost' renin-angiotenzin-al'dosteronovoi sistemy i uroven' vazopressina u patsientov s pervichnoi legochnoi gipertoniei.

AIM: Assessment of RAAS and vasopressin in patients with primary pulmonary hypertension (PPH). MATERIALS AND METHODS: Activity of plasma renin (APR), angiotensin-converting enzyme (ACE), plasma levels of angiotensin II (AII) and vasopressin (VP), serum concentration of aldosteron (AS) were measured by radioimmunoassay and enzyme immunoassay in 21 PPH patients with circulatory failure (age 34.7 +/- 2.1 years), 11 patients with NYHA functional class II-III, 10 with class IV, and 10 control subjects (age 29.8 +/- 1.5 years). RESULTS: Compared to controls, 21 PPH patients had elevated RAAS parameters: APR up to 3.52 ng/ml/h (p < 0.05), activity of ACE up to 43.13 units, AII level up to 33.93 ng/ml (p < 0.01), AS up to 468.86 ng/ml (p < 0.01), VP up to 5.26 ng/ml (p < 0.001). Circulatory failure progression resulted in activation of all the RAAS components. This and VP activation was the greatest in PPH patients with ACE > 5 ng/ml/h. PPH patients with mean pressure in the pulmonary artery higher than 60 mm Hg demonstrated higher ARP, AS, VP, AII, ACE than those who had this pressure under 60 mm Hg. CONCLUSION: PPH patients display a noticeable activation of RAAS and VP. This activation seems to be secondary as the changes increase with elevation of the pressure in the pulmonary artery and aggravation of circulatory insufficiency. Plasma renin activity determines the degree of RAAS activation as a whole. The discovered activation of RAAS in PPH gives grounds for doubts in the validity of using ACE inhibitors in the treatment of PPH.

[Problems in the diagnosis and clinical assessment of atrial dissociation (a report on 2 cases and review of the literature)]. / Voprosy diagnostiki i klinicheskoi otsenki predserdnoi dissotsiatsii (soobshchenie o dvukh sluchaiakh nabliudeniia i obzor literatury).

At registration of ECG esophageal leads in two patients with ischemic heart disease an extra atrial rhythm was recorded missed by standard ECG. Similar cases from the literature are considered.

[Methodologic features of determining renin-like activity in human arteries]. / Metodicheskie osobennosti opredeleniia reninopodobnoi aktivnosti arterii cheloveka.

Human arterial tissue was shown to have renin-like activity. For its determination the authors propose methodological approaches. The optimum pH of renin activity in the vascular wall was found to be 5.8-6.0. The renin-like enzyme was ascertained to be present in the vascular wall as inactive and to be activated by trypsin. The renin activity was compared in the human vascular wall and human plasma. Their optimum pHs were nearly identical. The methodological features determined in this paper allowed one to differentiate the true renin-like activity from the activity of acid proteases.

[Functional state of the adrenals in various forms of arterial hypertension]. / Otsenka funktsional'nogo sostoianiia nadpochechnikov pri nekotorykh formakh arterial'noi gipertenzii.

The study of structural changes and changes of the aldosterone content (AC) in the surgically removed adrenals of patients with different clinical variants of combination of the arterial hypertension (AH), low--renin hyperaldosteronism and space--occupying lesions in the adrenals found by CT was carried out. In 15 of 20 patients after adrenalectomy the diagnosis of the primary aldosteronism (PA) was established, in 4 cases diagnosis of the hypertension, 2B degree, and in one case the diagnosis of Cushing disease. The functional state was evaluated according to AC in the adenomas and macronodes and in the adjacent cortex as well as by nuclei size of cells producing aldosterone. The aldosterone hyperproduction was shown to be associated with local adenoma in some cases and with hyperactive cortex in the others this being reflected in the course of AH and in the adrenalectomy hypotensive effect.

[The diagnostic importance of determining prostaglandins in patients with nephrogenic arterial hypertension]. / Diagnosticheskoe znachenie opredeleniia prostaglandinov u bol'nykh nefrogennoi arterial'noi gipertenziei.

The study included 15 patients with nephrogenic hypertension of various genesis. 13 of them had unilateral disease, 2 bilateral one. The diagnosis was established from the data provided by a single captopril test, radionuclide and angiographic examinations. The blood for renin and prostaglandin quantitation was obtained from the renal veins and infrarenal portion of the vena cava inferior. The results show that in unilateral renal lesions prostaglandin E secretion on the affected side was significantly lower than on the contralateral side (p less than 0.05). Plasma renin activity in 3 patients with a contracted kidney was significantly lower on the affected side (p less than 0.05), though the rest 10 patients were reported to exhibit opposite results. No significant relationships occurred in the levels of prostaglandins I2, F2 alpha, thromboxane A2. It is suggested that renal ischemia may inhibit synthesis of depressor prostaglandin E2 in renal medullary interstice. A separate analysis is presented of plasma renin and prostaglandin activity in 2 cases of nephrogenic hypertension as a result of bilateral renal affection.

[Renin-angiotensin system in sudden cardiac death: biochemical and morphological aspects]. / Renin-angiotenzinnaia sistema pri vnezapnoi sedechnoi smerti: biokhimicheskie i morfologicheskie aspekty.

The renin activity of the blood plasma (RAP), renal cortex (RARC), juxtaglomerular apparatus (JGA) and renal microcirculation were studied in 330 male patients after sudden death. The activity of the renin-angiotensin system (RAS) is shown to be increased in sudden cardiac death (SCD) particularly in patients dying in the presence of alcoholic intoxication. The values of RAP and RARC and their correlation depend on the ethanol concentration in the blood. In cases of SCD with chronic alcoholic intoxication the signs of JGA hyperfunction are found (diffuse hypertrophy of the JGA structural elements). The investigation of the kidney microcirculation revealed two main phenomena of the circulation disturbance--juxtamedullary shunting and congestion. The interconnection between the degree of RAS activity and the type of the microcirculatory damage is established. The congestion was more frequently observed at the low and medium RAP values while the juxtamedullary shunting--at the high levels of the renin activity.

[Alcohol and hypertension in sudden cardiac death, features of the status of the renin-angiotensin-aldosterone system]. / Alkogol' i gipertoniia pri vnezapnoi serdechnoi smerti, osobennosti sostoianiia renin-angiotenzin-al'dosteronovoi sistemy.

The activity of blood plasma renin and the renal cortical layer in persons who had suddenly died, was much lower in those with arterial hypertension than in those without it. A more pronounced increase in the activity of blood plasma renin and the renal cortex was noted in persons with hypertension who had died against a background of alcoholic intoxication as compared to persons without hypertension. In sudden cardiac death of persons without hypertension there was a positive correlation between plasma renin activity and alcohol concentration in the blood. Such a correlation was undetectable in the presence of hypertension. In small alcohol concentrations in the blood higher plasma renin activity values were noted in persons with hypertension than in those without it. Aldosterone concentration in the blood of patients with arterial hypertension and without it did not practically differ. The presence of alcohol in persons without hypertension resulted in a significant increase in aldosterone concentration in sudden cardiac death as compared to those with hypertension. A positive correlation between renin activity and aldosterone concentration was noted in all the groups under study.

[Renin activity and plasma aldosterone level after sudden death from alcoholic intoxication]. / Aktivnost' renina i kontsentratsiia al'dosterona v plazme pri vnezapnoi serdechnoi smerti lits s alkogol'noi intoksikatsiei.

Plasma renin activity (PRA) and aldosterone concentration (PAC) were determined in early (up to 6 hours) autopsy material of 35 cases of sudden death (men aged 22-35). In half of cases alcohol was present in the blood. The same parameters were evaluated in 35 living men: 17 donors and 18 subjects with alcoholic intoxication. The presence of alcohol in the blood both in cases of sudden cardiac death (SCD) and in subjects with alcoholic intoxication was shown to result in a marked increase in PRA and PAC. Statistic analysis revealed a positive correlation between PRA and PAC in SCD in the presence of alcoholic intoxication, which is not observed when the latter is absent. These results suggest that aldosterone concentration in SCD may be increased due to some stimulating factors other than alcohol. Calcium balance disturbances could be one of them.

[Microcirculatory characteristics in the kidneys in sudden cardiac death]. / Osobennosti mikrotsirkuliatsii v pochkakkh pri vnezapnoi serdechnoi smerti.

Disorder of microcirculation in different organs, including kidney, is one of the pathomorphological features of sudden cardiac death (SCD). The paper presents the report on renal microcirculation pattern in 345 cases of SCD. Disorders of renal microcirculatory system were noted in half of SCD cases and they were mainly expressed in 2 ways, either as a juxtamedullary shunting, or excessive plethora with signs of intravascular hypercoagulation. Comparison of morphologic data with a number of additional indices allows one to conclude that incidence and character of microcirculatory disorders depend on a number of factors, such as sudden death, the activity of renin-angiotensin system, alcohol intoxication and hypertonic nephroangiosclerosis.

[Atherosclerotic stenosis of the coronary arteries and contraction lesions of the myocardium in sudden coronary death]. / Ateroskleroticheskii stenoz koronarnykh arterii i kontrakturnye povrezhdeniia miokarda pri vnezapnoi koronarnoi smerti.

Hearts of 50 patients (males of 30 to 54 years) after sudden cardiac death (SCD) without myocardial infarction, acute or recorded in the past, were studied. Heart slides were stained with an iron hematoxylin; polarizing microscopy was also used. The surface of cardiomyocytes diffusely stained with an iron hematoxylin was determined in histological slides by means of a 100-points ocular mesh. Essential differences in the spread of contractural myocardial lesions were found, this likely to be bound with different mechanisms of death (ventricular fibrillation, asystole). A low degree of spread of these lesions was noted more frequently in grave stenoses (greater than 75%) of coronary arteries. A direct correlation between the spread of contractural lesions and renin activity in plasma is found.

[Renin activity in plasma and kidneys upon sudden death of hypertension patients]. / Aktivnost' renina v plazme krovi i pochkakh pri vnezapnoi serdechnoi smerti u bol'nykh arterial'noi gipertoniei.

Activity of blood plasma renin and renal cortical tissue was studied in conditions of sudden cardiac death in patients with and without arterial hypertension and also in blood donors. The renin activity in the blood of those who died suddenly was 2.5 times higher than in the donors. Comparing renin activity in sudden cardiac death showed that in the hypertensive deceased, this indicator in both plasma and kidneys was lower than in normotensive patients. The renin activity in plasma and the kidneys of those who died suddenly was higher in patients with symptomatic hypertension as compared to those suffering from essential hypertension. Under conditions of sudden heart death, the elevated renin activity in hypertensive patients occurred twice less frequently as against normotensives. The study also disclosed age-specific changes of the renin activity in blood plasma and renal cortical tissue; with age it tended to decline both in plasma and kidneys. Similar results were also obtained for plasma renin activity in the donors.

[Cardiogenic shock and sudden cardiac death]. / Kardiogennyi shok i vnezapnaia serdechnaia smert'.

The study of 148 cases of sudden cardiac death revealed in 25 (17%) of them morphological signs of cardiogenic shock characterized by severe microcirculatory disorders: uneven blood-filling of the vessels of the microcirculatory bed and increasing number of nonfunctioning capillaries in the myocardium and hypothalamus; signs of juxtamedullar shunting in the kidneys and the development of sludge phenomenon in different parts of their microcirculatory bed combined with high activity of renin in the plasma. The signs of cardiogenic shock in the group of observations of sudden cardiac death were noted predominantly in the presence of myocardial infarction, large foci of ischemia in the heart or multiple scattered foci of cardiomyocyte damage. Cardiogenic shock was found to occur in sharp reduction of the density of adrenergic nerve structures in the myocardium.

[Memory disorders in vascular lesions of the brain]. / Osobennosti rasstroistv pamiati pri sosudistykh porazheniiakh golovnogo mozga.

The authors studied clinical and psychological features in disorders of memory due to vascular brain lesions. With the aid of pyktograms the character of activities of the examinees during the process of perception and differences in disorders of moderation in patients with lesions of the frontal and occipital parts of the brain were demonstrated. It is established that in the initial stages of the mnestic process the leading role is played by frontal lobes, while in latent reproductivity the significance of occipital brain areas increases.